vimeo/psalm

array_unique 2nd parameter may restrict the array items type

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#7,956 opened on May 13, 2022

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 (11 comments) (0 reactions) (0 assignees)PHP (5,369 stars) (668 forks)batch import
Help wantedeasy problemsinternal stubs/callmap

Description

Hi,

the array_unique() function has an optional 2nd parameter flag, which is one of the following value:

  • SORT_REGULAR
  • SORT_NUMERIC
  • SORT_STRING (default value)
  • SORT_LOCALE_STRING

if the flag is one of SORT_LOCALE or SORT_LOCALE_STRING, the array should only contain strings or values that can be casted to string. I'm not sure exactly what the definition should be, maybe: int|float|string|bool|\Stringable|null

Here we can see it fail : https://3v4l.org/lJsCp

and here we can see that Psalm does not find any error: https://psalm.dev/r/2135f5de25

edit: I realized that the SORT_NUMERIC also restrict the item type, probably something like int|float|string|null

Contributor guide

Tech stack
None
Domain
backendtooling
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
fresh
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
PHP basics
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70
Research direction
The issue requires updating the type definition for array unique in Psalm's function stubs (likely in stubs/Php72.php or similar). The behavior should detect the second parameter flag and accordingly restrict the item type. The examples from the issue and the Psalm dev playground link can be used to test. No linked PRs or comments suggesting a specific solution.